The invention relates generally to inductive pick-up devices and, more particularly, to inductive pick-up devices employing diversity and adaptive antenna arrangements.
Inductive pick-ups are currently being used to provide frame rate synchronization to media monitoring systems (e.g., television and computer monitors) and for determining what watermark has been encoded into video content thereby identifying the program source. Such pick-ups come in two varieties: (i) one picks up the video noise generated by the electron guns of the monitor; and (ii) the other is installed in a position specifically determined to have the best signal for intercepting the intermediate radio frequency signal, typically at about 44 Megahertz (MHZ). The best position to detect this frequency is not always the same location and, therefore, the position of the pick-up with respect to the monitor needs to be optimized manually.
Advantages to locating a pick-up on the back of the monitor include: (i) higher signal level for detection and interpretation of in-content video encoding or watermarking; (ii) ease of installation; (iii) low cost. However, a disadvantage is that the pick-up located on the back of the monitor detects little of the intermediate frequency.
An advantage to locating a pick-up on the underside of the monitor is that the pick-up receives the intermediate frequency and thereby includes both audio and video, as well as the vertical blanking interval. One problem associated with antennas of this type includes the complexity of installation in an appropriate location so as to get a sufficient signal for detecting data or a watermark.
Conventional systems require a trained expert to select a position near the monitor, evaluate the signal received and determine the best location for the antenna so that a high quality signal can be received. Since there is a high degree of variation among monitors, there is no specific location that is best suited to receive a signal from every monitor.
Therefore, there is a need for an improved inductive pick-up arrangement which at least substantially eliminates the need to manually optimize the pick-up location with respect to the monitor, thus obviating the need for a trained expert to position the pick-up.
The present invention provides for inductive pick-up devices employing diversity and adaptive antenna arrangements. By utilizing diversity and/or adaptive antennas, as will be explained, the pick-up can be installed by a consumer without use of a computer monitor or other device to determine alignment. In addition, the arrangements described herein increase the level of signal available to a data decoding system.
Thus, one important purpose of creating such an antenna array in accordance with the invention is to reduce the expertise required to obtain a satisfactory signal from outside a device, such as a television, such that a data stream encoded into the video may be decoded easily, inexpensively, and without risk of capturing the wrong signal from a programming transmission, that is, a transmission that is not currently being viewed by a consumer.
Separate diversity antenna arrangements may be employed, as well as separate adaptive antenna arrangements. In one preferred embodiment, a pick-up arrangement employ both diversity and adaptive antennas is used. In combining the two types of antenna arrays in a pick-up and using the best features of both, we additionally gain performance on synchronizing frame rate and picking up data.
In accordance with one aspect of the invention, a predetermined number of antennas are arranged in a single pick-up device. In one embodiment, the arrangement may comprise four antennas. Each of the predetermined number of antennas pick up a signal from the environment. In the case of the diversity antenna arrangement, the system continually samples the signal received by each antenna and switches data collection functions to the antenna receiving the signal determined to be the best. In the case ofthe adaptive antenna arrangement, signals received by each of the antennas are added together to provide a more robust signal for data collection and processing. As mentioned, in one embodiment, both a diversity approach and an adaptive approach are employed together. It is to be appreciated that these approaches can be used for either of the pick-up devices described above, i.e., (i) one that picks up the video noise generated by the electron guns of the monitor; and (ii) the other that intercepts the intermediate radio frequency signal.
Advantageously, a pick-up formed according to the present invention substantially eliminates the most significant problem encountered when using a conventional pick-up, i.e., being required to have the pick-up installed in an optimal location by a skilled person.
It is to be further appreciated that more than one pick-up arrangement may be placed around the display device being monitored. A pick-up on the back of the monitor provides a better level of signal from which the video encoded watermark or data can be decoded, however, the vertical blanking interval is not as easy to detect. By using the pick-up under the monitor to correct and synchronize the timing elements associated with decoding sequences, we improve the system""s ability to provide more and more accurate bits from the video stream. By combining a pick-up under the monitor with a pick-up on the sloping back of the monitor, for example, we substantially improve the throughput of the data captured for any number of applications.
Applications may, for example, include: proof of performance, data delivery, program ratings, direct response, system control. However, the invention is not limited to any particular application.
In an embodiment where the present invention is employed in accordance with a television monitor having a set top box associated therewith, the data captured and decoded by an antenna array arrangement of the invention may be compared to the data decoded by the set top box. If the decoded data is different, then the data captured and decoded by the antenna array arrangement is used by the application. Otherwise, the set top box decoded data is used.
The performance of a system according to the invention is especially significant in a digital television environment. In the digital television environment, information encoded into the vertical blanking intervals will not be available to such monitoring systems. As many as six video streams can be broadcast on the same channel, so determining viewer content becomes impossible without reliable inductive pick-ups when access to the data stream has not been provided directly by television equipment manufacturers.
These and other objects, features and advantages of the present invention will become apparent from the following detailed description of illustrative embodiments thereof, which is to be read in connection with the accompanying drawings.